Galaga is a fixed shooter arcade game developed and published by Namco in Japan and published by Midway in North America in 1981. It is the sequel to Galaxian, released in 1979. The gameplay of Galaga puts the player in control of a space ship which is situated at the bottom of the screen. At the beginning of each stage, the area is empty, but over time, enemy aliens will arrive in formation, and once all of the enemies arrive on screen, they will come down at the player's ship in formations of one or more and may either shoot it or collide with it. During the entire stage, the player may fire upon the enemies, and once all enemies are vanquished, the player will proceed to the next stage.
Galaga is one of the most successful games from the Golden Age of Video Arcade Games. The arcade version of it has been ported to many consoles, and it has had several sequels.
The objective of Galaga is to score as many points as possible by destroying insect-like enemies. The player controls a starfighter that can move left and right along the bottom of the playfield. Enemies swarm in groups in a formation near the top of the screen, and then begin flying down toward the player, firing bullets at and attempting to crash into them. In later stages, some enemies even break from an entering group to frantically try to crash into the player. The game ends when the player's last fighter is lost, either by colliding with an enemy, one of its bullets, or by being captured.
Galaga introduces a number of new features over its predecessor, Galaxian. Among these are the ability to fire more than one shot at a time, a count of the player's 'hit/miss ratio' at the end of the game, and a bonus 'Challenging Stage' that occurs every few stages, in which a series of enemies fly onto and off the screen in set patterns without firing at the player's ship or trying to crash into it. These stages award a 10,000-point bonus if the player manages to destroy every enemy, but otherwise 100 bonus points for every enemy destroyed.
Another gameplay feature new to Galaga is the ability for enemies to capture the player's fighter. While the player is in control of just one fighter, a 'boss' Galaga (which takes two hits to kill) will periodically attempt to capture the fighter using a tractor beam. If successful, the fighter joins the enemy formation as a satellite to the boss Galaga which captured it. The captive fighter becomes an enemy, and likewise, it can be shot and destroyed. The player can still fire while being captured up to the point their ship 'touches' the captor, which could be considered an opportunity to shoot the captor down before it can manage to successfully capture the player. Captive fighters can be freed by destroying the boss Galaga towing it while it is attacking. The freed fighter will then combine with the player's fighter who freed them, offering doubled firepower but with the disadvantage of a target twice as large. If the player destroys the captor while it is still in formation, the captured fighter will not be rescued, and will instead fly away after a diving run (assuming the player does not destroy it) to appear in the next stage as a satellite for another boss Galaga where it can once again be rescued.